Revenue for Internet companies is often driven by advertising, which is paid out based on the number of network interactions (e.g., a click) on an advertisement. However, sometimes network interactions are not legitimate—for example, a botnet may be developed to cause network interactions with an advertisement. Illegitimate network interactions lead to inappropriate payments by advertisers and inappropriate payments to publishers. It would be useful to be able to analyze network interactions to assess their legitimacy to reduce the amount of inappropriate payments.